U.S. patent application number 15/043933 was filed with the patent office on 2017-08-17 for gas turbine engine trailing edge ejection holes.
The applicant listed for this patent is GENERAL ELECTRIC COMPANY. Invention is credited to JAMES HERBERT DEINES, WESTON NOLAN DOOLEY, DOUGLAS GERARD KONITZER, MATTHEW LEE KRUMANAKER.
Application Number | 20170234137 15/043933 |
Document ID | / |
Family ID | 58043951 |
Filed Date | 2017-08-17 |
United States Patent
Application |
20170234137 |
Kind Code |
A1 |
KONITZER; DOUGLAS GERARD ;
et al. |
August 17, 2017 |
GAS TURBINE ENGINE TRAILING EDGE EJECTION HOLES
Abstract
An apparatus and method for an airfoil for a gas turbine engine
includes a trailing edge cooling circuit utilizing a plurality of
trailing edge ejection holes. The ejection holes can include a
circumferentially radiused inlet, a converging section, a metering
section, and a diverging section to improve airfoil cooling as well
as castability.
Inventors: |
KONITZER; DOUGLAS GERARD;
(WEST CHESTER, OH) ; KRUMANAKER; MATTHEW LEE;
(BLUE ASH, OH) ; DOOLEY; WESTON NOLAN; (WEST
CHESTER, OH) ; DEINES; JAMES HERBERT; (MASON,
OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GENERAL ELECTRIC COMPANY |
SCHENECTADY |
NY |
US |
|
|
Family ID: |
58043951 |
Appl. No.: |
15/043933 |
Filed: |
February 15, 2016 |
Current U.S.
Class: |
416/1 |
Current CPC
Class: |
F05D 2240/122 20130101;
F01D 9/065 20130101; F05D 2250/323 20130101; F05D 2260/2214
20130101; F01D 5/186 20130101; F05D 2250/324 20130101; F05D
2250/712 20130101; Y02T 50/676 20130101; F05D 2240/304 20130101;
Y02T 50/60 20130101 |
International
Class: |
F01D 5/18 20060101
F01D005/18 |
Claims
1. An airfoil for a turbine engine, the airfoil comprising: an
outer surface defining a pressure side and a suction side extending
axially between a leading edge and a trailing edge defining a
chord-wise direction and extending radially between a root and a
tip defining a span-wise direction; a cooling circuit located
within the airfoil and having a cooling passage extending from the
root toward the tip; and a plurality of trailing edge ejection
holes provided in the cooling passage in the span-wise direction
and an axial flow arrangement of a circumferentially radiused inlet
section, a converging section, a metering section, and a diverging
section.
2. The airfoil of claim 1 wherein the converging section includes a
decreasing cross-sectional area to accelerate a flow of air into
the trailing edge ejection hole.
3. The airfoil of claim 2 wherein the diverging section includes an
increasing cross-sectional area to decelerate the flow of air
exiting the trailing edge ejection hole.
4. The airfoil of claim 3 wherein the diverging section defines an
expansion angle being 7 degrees or less.
5. The airfoil of claim 1 wherein a centerline of the trailing edge
ejection holes are parallel to one of the pressure side or suction
side.
6. The airfoil of claim 1 wherein a centerline of the trailing edge
ejection holes equally bisects the airfoil.
7. The airfoil of claim 1 wherein the metering section has a length
and a diameter defining a length to diameter ratio of at least
1.
8. The airfoil of claim 7 wherein the length to diameter ratio is
2.
9. The airfoil of claim 7 wherein the length of the metering
section is 40 mils.
10. The airfoil of claim 1 wherein the converging section and
diverging section define a linear centerline.
11. The airfoil of claim 1 wherein the converging section, the
metering section, and the diverging section define a non-linear
centerline.
12. The airfoil of claim 1 wherein the trailing edge ejection holes
are arranged in two or more groups disposed along the trailing
edge.
13. The airfoil of claim 1 wherein the trailing edge ejection holes
are arranged along the span-wise extend to the trailing edge and
the trailing edge ejection holes near middle of the airfoil in the
span-wise direction have a larger width than the ejection holes
near the root and the tip.
14. The airfoil of claim 1 wherein the airfoil is at least one of a
blade or a vane.
15. The airfoil of claim 1 further comprising a plurality of
turbulators disposed in the trailing edge ejection holes.
16. An airfoil for a turbine engine, the airfoil comprising a
cooling circuit having a cooling passage extending from a root
toward a tip in a span-wise direction with a plurality of trailing
edge ejection holes provided in the cooling passage including a
circumferentially radiused inlet section, an converging section, a
metering section, and a diverging section.
17. The airfoil of claim 16 wherein the converging section includes
a decreasing cross-sectional area to accelerate a flow of air into
the trailing edge ejection holes.
18. The airfoil of claim 17 wherein the diverging section includes
an increasing cross-sectional area to decelerate the flow of air
exiting the trailing edge ejection holes.
19. The airfoil of claim 18 wherein the diverging section defines
an expansion angle being 7 degrees or less.
20. The airfoil of claim 16 wherein a centerline of the trailing
edge ejection holes is parallel to one of a pressure side or a
suction side.
21. The airfoil of claim 16 wherein a centerline of the trailing
edge ejection holes equally bisects the airfoil.
22. The airfoil of claim 16 wherein the metering section has a
length and a diameter defining a length to diameter ratio of at
least 1.
23. The airfoil of claim 22 wherein the length to diameter ratio is
2.
24. The airfoil of claim 16 wherein the airfoil is at least one of
a blade or a vane.
25. The airfoil of claim 16 further comprising a plurality of
turbulators disposed in the trailing edge ejection holes.
26. A method of providing a flow of cooling fluid through a
plurality of trailing edge ejection holes in an airfoil, the method
comprising: accelerating the flow of cooling fluid into one or more
trailing edge ejection holes; and decelerating the flow of cooling
fluid exiting the trailing edge ejection holes.
27. The method of claim 26 further comprising metering the flow of
cooling fluid through the trailing edge ejection holes.
28. The method of claim 27 wherein the accelerating is done prior
to the metering.
29. The method of claim 28 wherein the metering is done prior to
the decelerating.
30. The method of claim 29 further comprising exhausting the
decelerated flow to a trailing edge channel.
31. The method of claim 29 further comprising exhausting the
decelerated flow through a trailing edge slot opening.
Description
BACKGROUND OF THE INVENTION
[0001] Turbine engines, and particularly gas or combustion turbine
engines, are rotary engines that extract energy from a flow of
combusted gases passing through the engine onto a multitude of
rotating turbine blades.
[0002] Gas turbine engines for aircraft are designed to operate at
high temperatures to maximize engine efficiency, so cooling of
certain engine components, such as the high pressure turbine and
the low pressure turbine, can be beneficial. Typically, cooling is
accomplished by ducting cooler air from the high and/or low
pressure compressors to the engine components that require cooling.
Temperatures in the high pressure turbine are around 1000.degree.
C. to 2000.degree. C. and the cooling air from the compressor is
around 500.degree. C. to 700.degree. C. While the compressor air is
a high temperature, it is cooler relative to the turbine air, and
can be used to cool the turbine.
[0003] Contemporary turbine blades generally include one or more
interior cooling circuits for routing the cooling air through the
blade to cool different portions of the blade, and can include
dedicated cooling circuits for cooling different portions of the
blade, such as the leading edge, trailing edge and tip of the
blade.
BRIEF DESCRIPTION OF THE INVENTION
[0004] In one aspect, embodiments of the invention relate to an
airfoil for a gas turbine engine including an outer surface
defining a pressure side and a suction side extending axially
between a leading edge and a trailing edge defining a chord-wise
direction and extending radially between a root and a tip defining
a span-wise direction. The airfoil further includes a cooling
circuit located within the airfoil and having a cooling passage
extending from the root toward the tip and a plurality of trailing
edge ejection holes provided in the cooling passage in the
span-wise direction and an axial flow arrangement of a
circumferentially radiused inlet section, a converging section, a
metering section, and a diverging section.
[0005] In another aspect, embodiments of the invention relate to an
airfoil for a gas turbine engine including a cooling circuit having
a cooling passage extending from a root toward a tip in a span-wise
direction with a plurality of trailing edge ejection holes provided
in the cooling passage including a circumferentially radiused inlet
section, a converging section, a metering section, and a diverging
section.
[0006] In yet another aspect, embodiments of the invention relate
to a method of providing a flow of cooling fluid through a
plurality of trailing edge ejection holes includes accelerating the
flow of cooling fluid into the trailing edge ejection holes and
decelerating the flow of cooling fluid exiting the trailing edge
ejection holes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] In the drawings:
[0008] FIG. 1 is a schematic cross-sectional diagram of a gas
turbine engine for an aircraft.
[0009] FIG. 2 is an isometric view of an airfoil of the engine of
FIG. 1 in the form of a blade.
[0010] FIG. 3 is a cross-section of the airfoil of FIG. 2
illustrating a trailing edge circuit.
[0011] FIG. 4 is a flow diagram illustrating the trailing edge
circuit of FIG. 3.
[0012] FIG. 5 is core view of the trailing edge circuit of FIG.
4.
[0013] FIG. 6 is a close-up view of trailing edge ejection holes of
the core of FIG. 5.
[0014] FIG. 7 is a schematic view illustration the geometry of one
trailing edge ejection hole of FIG. 6.
[0015] FIG. 8 is a flow chart of a method of providing a flow of
cooling fluid through the trailing edge circuit.
DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0016] The described embodiments of the present invention are
directed to a plurality of trailing edge ejection holes arranged
within an airfoil for a gas turbine engine. For purposes of
illustration, the present invention will be described with respect
to the turbine for an aircraft gas turbine engine. It will be
understood, however, that the invention is not so limited and may
have general applicability within an engine, including compressors,
as well as in non-aircraft applications, such as other mobile
applications and non-mobile industrial, commercial, and residential
applications.
[0017] As used herein, the term "forward" or "upstream" refers to
moving in a direction toward the engine inlet, or a component being
relatively closer to the engine inlet as compared to another
component. The term "aft" or "downstream" used in conjunction with
"forward" or "upstream" refers to a direction toward the rear or
outlet of the engine relative to the engine centerline.
[0018] Additionally, as used herein, the terms "radial" or
"radially" refer to a dimension extending between a center
longitudinal axis of the engine and an outer engine
circumference.
[0019] All directional references (e.g., radial, axial, proximal,
distal, upper, lower, upward, downward, left, right, lateral,
front, back, top, bottom, above, below, vertical, horizontal,
clockwise, counterclockwise, upstream, downstream, aft, etc.) are
only used for identification purposes to aid the reader's
understanding of the present invention, and do not create
limitations, particularly as to the position, orientation, or use
of the invention. Connection references (e.g., attached, coupled,
connected, and joined) are to be construed broadly and can include
intermediate members between a collection of elements and relative
movement between elements unless otherwise indicated. As such,
connection references do not necessarily infer that two elements
are directly connected and in fixed relation to one another. The
exemplary drawings are for purposes of illustration only and the
dimensions, positions, order and relative sizes reflected in the
drawings attached hereto can vary.
[0020] FIG. 1 is a schematic cross-sectional diagram of a gas
turbine engine 10 for an aircraft. The engine 10 has a generally
longitudinally extending axis or centerline 12 extending forward 14
to aft 16. The engine 10 includes, in downstream serial flow
relationship, a fan section 18 including a fan 20, a compressor
section 22 including a booster or low pressure (LP) compressor 24
and a high pressure (HP) compressor 26, a combustion section 28
including a combustor 30, a turbine section 32 including a HP
turbine 34, and a LP turbine 36, and an exhaust section 38.
[0021] The fan section 18 includes a fan casing 40 surrounding the
fan 20. The fan 20 includes a plurality of fan blades 42 disposed
radially about the centerline 12. The HP compressor 26, the
combustor 30, and the HP turbine 34 form a core 44 of the engine
10, which generates combustion gases. The core 44 is surrounded by
core casing 46, which can be coupled with the fan casing 40.
[0022] A HP shaft or spool 48 disposed coaxially about the
centerline 12 of the engine 10 drivingly connects the HP turbine 34
to the HP compressor 26. A LP shaft or spool 50, which is disposed
coaxially about the centerline 12 of the engine 10 within the
larger diameter annular HP spool 48, drivingly connects the LP
turbine 36 to the LP compressor 24 and fan 20.
[0023] The LP compressor 24 and the HP compressor 26 respectively
include a plurality of compressor stages 52, 54, in which a set of
compressor blades 56, 58 rotate relative to a corresponding set of
static compressor vanes 60, 62 (also called a nozzle) to compress
or pressurize the stream of fluid passing through the stage. In a
single compressor stage 52, 54, multiple compressor blades 56, 58
can be provided in a ring and can extend radially outwardly
relative to the centerline 12, from a blade platform to a blade
tip, while the corresponding static compressor vanes 60, 62 are
positioned upstream of and adjacent to the rotating blades 56, 58.
It is noted that the number of blades, vanes, and compressor stages
shown in FIG. 1 were selected for illustrative purposes only, and
that other numbers are possible.
[0024] The blades 56, 58 for a stage of the compressor can be
mounted to a disk 59, which is mounted to the corresponding one of
the HP and LP spools 48, 50, with each stage having its own disk
59, 61. The vanes 60, 62 for a stage of the compressor can be
mounted to the core casing 46 in a circumferential arrangement.
[0025] The HP turbine 34 and the LP turbine 36 respectively include
a plurality of turbine stages 64, 66, in which a set of turbine
blades 68, 70 are rotated relative to a corresponding set of static
turbine vanes 72, 74 (also called a nozzle) to extract energy from
the stream of fluid passing through the stage. In a single turbine
stage 64, 66, multiple turbine vanes 72, 74 can be provided in a
ring and can extend radially outwardly relative to the centerline
12, while the corresponding rotating blades 68, 70 are positioned
downstream of and adjacent to the static turbine vanes 72, 74 and
can also extend radially outwardly relative to the centerline 12,
from a blade platform to a blade tip. It is noted that the number
of blades, vanes, and turbine stages shown in FIG. 1 were selected
for illustrative purposes only, and that other numbers are
possible.
[0026] The blades 68, 70 for a stage of the turbine can be mounted
to a disk 71, which is mounted to the corresponding one of the HP
and LP spools 48, 50, with each stage having its own disk 71, 73.
The vanes 72, 74 for a stage of the compressor can be mounted to
the core casing 46 in a circumferential arrangement.
[0027] The portions of the engine 10 mounted to and rotating with
either or both of the spools 48, 50 are also referred to
individually or collectively as a rotor 53. The stationary portions
of the engine 10 including portions mounted to the core casing 46
are also referred to individually or collectively as a stator
63.
[0028] In operation, the airflow exiting the fan section 18 is
split such that a portion of the airflow is channeled into the LP
compressor 24, which then supplies pressurized ambient air 76 to
the HP compressor 26, which further pressurizes the ambient air.
The pressurized air 76 from the HP compressor 26 is mixed with fuel
in the combustor 30 and ignited, thereby generating combustion
gases. Some work is extracted from these gases by the HP turbine
34, which drives the HP compressor 26. The combustion gases are
discharged into the LP turbine 36, which extracts additional work
to drive the LP compressor 24, and the exhaust gas is ultimately
discharged from the engine 10 via the exhaust section 38. The
driving of the LP turbine 36 drives the LP spool 50 to rotate the
fan 20 and the LP compressor 24.
[0029] A remaining portion of the airflow 78 bypasses the LP
compressor 24 and engine core 44 and exits the engine assembly 10
through a stationary vane row, and more particularly an outlet
guide vane assembly 80, comprising a plurality of airfoil guide
vanes 82, at the fan exhaust side 84. More specifically, a
circumferential row of radially extending airfoil guide vanes 82
are utilized adjacent the fan section 18 to exert some directional
control of the airflow 78.
[0030] Some of the ambient air supplied by the fan 20 can bypass
the engine core 44 and be used for cooling of portions, especially
hot portions, of the engine 10, and/or used to cool or power other
aspects of the aircraft. In the context of a turbine engine, the
hot portions of the engine are normally the combustor 30 and
components downstream of the combustor 30, especially the turbine
section 32, with the HP turbine 34 being the hottest portion as it
is directly downstream of the combustion section 28. Other sources
of cooling fluid can be, but is not limited to, fluid discharged
from the LP compressor 24 or the HP compressor 26. This fluid can
be bleed air 77 which can include air drawn from the LP or HP
compressors 24, 26 that bypasses the combustor 30 as cooling
sources for the turbine section 32. This is a common engine
configuration, not meant to be limiting.
[0031] FIG. 2 is a perspective view of an engine component in the
form of one of the turbine blades 68 of the engine 10 from FIG. 1.
The turbine blade 68 includes a dovetail 90 and an airfoil 92. The
airfoil 92 includes a tip 94 and a root 96 defining a span-wise
direction therebetween. The airfoil 92 mounts to the dovetail 90 at
a platform 98 at the root 96. The platform 98 helps to radially
contain the turbine engine mainstream air flow. The dovetail 90 can
be configured to mount to a turbine rotor disk 71 on the engine 10.
The dovetail 90 further includes at least one inlet passage 100,
exemplarily shown as a three inlet passages 100, each extending
through the dovetail 90 to provide internal fluid communication
with the airfoil 92 at a passage outlet 102. It should be
appreciated that the dovetail 90 is shown in cross-section, such
that the inlet passages 100 are housed within the body of the
dovetail 90.
[0032] Turning to FIG. 3, the airfoil 92, shown in cross-section,
has a concave-shaped pressure sidewall 110 and a convex-shaped
suction sidewall 112 which are joined together to define an airfoil
shape with a leading edge 114 and a trailing edge 116, defining a
chord-wise direction therebetween. The airfoil 92 has an interior
118 defined by the sidewalls 110, 112. The blade 68 rotates in a
direction such that the pressure sidewall 110 follows the suction
sidewall 112. Thus, as shown in FIG. 3, the airfoil 92 would rotate
upward toward the top of the page.
[0033] One or more ribs 120 can divide the interior 118 into
multiple cooling channels. A leading edge cooling channel 122 can
be disposed adjacent to the leading edge 114, and a mid channel 124
can be adjacent to the leading edge cooling channel 122. It should
be appreciated that the leading edge and mid channels 122, 124 are
exemplary, and can be single channels extending in the span-wise
direction, or can be complex cooling circuits, having multiple
features such as passages, channels, inlets, pin banks, circuits,
sub-circuits, film holes, plenums, mesh, turbulators, or otherwise
and such details are not germane to the invention.
[0034] A trailing edge circuit 126 can include a trailing edge
plenum 128, impingement holes 130, an exhaust passage 132, pin
holes 134, ejection holes 136, and a trailing edge slot opening
140. The impingement holes 130 fluidly couple the trailing edge
plenum 128 to the exhaust passage 132. The exhaust passage 132 is
fluidly coupled to the trailing edge 116 through the pin holes 134
and the ejection holes 136. The trailing edge circuit 126 and the
interior 118 are fluidly coupled to the exterior of the airfoil 92
via the trailing edge slot opening 140.
[0035] It should be appreciated that while the ejection holes 136
are disposed adjacent to the trailing edge 116, there can be an
additional channel or plenum disposed between the trailing edge
ejection holes 136 and the trailing edge 116. Such a channel can
extend the full span-wise length of the airfoil 92 or can include
discrete channels or even single exhaust holes, such as film holes
for exhausting the cooling fluid at the trailing edge.
[0036] Looking at FIG. 4 a flow diagram for the leading edge and
mid cooling channels 122, 124 and the trailing edge cooling circuit
126 are schematically illustrated. The airfoil 92 is schematically
shown in broken line to illustrate the general configuration of the
cooling channels and circuits 122, 124, 126 within the airfoil 92.
The airfoil 92 defines the interior 96 as a cavity extending from
the leading edge 114 to the trailing edge 116 in the chord-wise
direction and from the tip 94 to the root 96 in the span-wise
direction, and which can be divided into distinct channels or
passages by internal walls to form the cooling channels and
circuits 122, 124, 126 which direct a flow of cooling fluid through
the airfoil 92. A tip cooling passage 150, disposed above the tip
94 of the airfoil 92, can extend in a substantially chord-wise
direction from adjacent the leading edge 114 toward the trailing
edge 116. The tip cooling passage 150 provides a common passage for
the cooling channels and circuits 122, 124, 126 to exhaust the
cooling fluid, such that the cooling fluid can be exhausted from
the airfoil 92 if not being exhausted through one or more film
holes or other exits.
[0037] Each channel or circuit 122, 124, 126 can be fed with a flow
of cooling fluid from the inlet passages 100. Each inlet passage
100 can supply a cooling circuit individually, or multiple channels
or circuits 122, 124, 126 can be fed from a common inlet passage
100.
[0038] The trailing edge circuit 126, illustrated as being fed from
one inlet passage 100, can be provided with a flow of cooling fluid
in the trailing edge plenum 128 in a root 96 to tip 94 direction. A
portion of the flow of cooling fluid can be provided from the
trailing edge plenum 128 into the tip cooling passage 150 through a
tip duct 152. Additionally, a portion of the cooling fluid within
the tip duct 152 can be provided to a flag passage 154 where the
cooling fluid can be provided to a tip flag 156.
[0039] The remaining portion of the flow of cooling fluid within
the trailing edge plenum 128 can flow into a trailing edge mid
passage 132 through the plurality of impingement holes 130. Within
the mid passage 132 the cooling fluid passes through a pin bank 158
having multiple pins 134. From the pin bank 158, the cooling fluid
is passed to the trailing edge 116 through multiple trailing edge
ejection holes 136. Upon exiting the trailing edge ejection holes
136, the cooling fluid can be exhausted from the airfoil 92, being
in fluid communication with the tip flag 156 and the tip cooling
passage 150, where the cooling fluid can be exhausted through one
or more trailing edge slot openings 140 at the trailing edge
116.
[0040] It should be appreciated that cooling channels and circuits
122, 124, 126, as illustrated in FIG. 4 are exemplary of one
implementation of the cooling circuits within an airfoil 92 and
should not be construed as limited by the particular geometry,
passages, pin banks, film holes, or otherwise. It should be further
understood that while the cooling channels and circuits 122, 124,
126 are illustrated as generally moving from the leading edge 114
toward the trailing edge 116 or the trailing edge 116 toward the
leading edge 114, the illustration is only an exemplary depiction
of the cooling circuits themselves. The particular passages,
channels, inlets, or otherwise can flow in any direction relative
to the airfoil 92, such as in the trailing or leading edge 114, 116
direction, tip 94 or root 96 direction, or toward the pressure 110
or suction 112 sidewalls of the airfoil 92, or any combination
thereof.
[0041] Looking at FIG. 5, a core view of the trailing edge circuit
126 is illustrated, showing the trailing edge ejection holes 136
disposed in a span-wise manner adjacent to the trailing edge 116. A
plurality of turbulators 160 are disposed in the trailing edge
plenum 128 for enhancing the cooling fluid flow C as it passes
through the plenum 128. It should be understood that the core view
of FIG. 5 illustrates a solid view of what would be the hollow
interior of the airfoil 92 through which cooling air flows. The
trailing edge ejection holes 136 provide the cooling flow from the
pin bank 158 or the tip flag 156 to the trailing edge 116.
[0042] FIG. 6 illustrates a close-up view of the trailing edge 116,
illustrating a portion of the ejection holes 136 and the pin bank
158. The ejection holes 136 are shaped having an inlet 170, a
conduit 172, and an outlet 174. The flow of cooling air exiting the
pin bank 158 is provided to the ejection holes 136 at the inlet
170. The flow of cooling air passes through the conduit 172 and is
exhausted from the ejection holes 136 at the outlet 174. The
exhausted cooling flow is provided to the trailing edge 116 where
it can be exhausted from the airfoil 92.
[0043] Looking at FIG. 7, the inlet 170 can have a
circumferentially radiused inlet 180 at the internal intersection
between the ejection hole 136 and the internal air supply. The
circumferentially radiused inlet 180 provides a flow of cooling
fluid C to a converging section 182. The flow of cooling fluid C
entering inlet radius 180 passes into the converging section 182,
where the flow of cooling fluid C is accelerated by a decreasing
cross-sectional area of the converging section 182, being provided
to the conduit 172. The conduit 172 can define a metering section
184 to meter the flow of cooling fluid C passing through the
ejection hole 136. From the metering section 184, the flow of
cooling fluid C passes to a diverging section 186 for decelerating
the cooling flow C through an increasing cross-sectional area,
being provided to the trailing edge 116.
[0044] A hole centerline 190 can be defined as the meanline axis
extending through the ejection holes 136. The centerline 190 can be
linear or non-linear, and can be disposed parallel to the pressure
sidewall 110 or the suction sidewall 112, or can define an angle
bisecting the airfoil 92 into two equal or unequal halves. A
diverging axis 192 can be defined as the linear line connecting the
end of the metering section 184 to the outlet 174. An expansion
angle 194 can be the angle between the hole centerline 190 and the
diverging axis 192, such that the cooling flow does not detach from
the wall. The expansion angle 194, for example, can be an angle of
seven degrees or less in non-limiting examples, while a larger
angle is contemplated.
[0045] Additionally, the metering section 184 can have a length and
a diameter such that a ratio of length to diameter is at least 1.0,
and can be 2.0. In one example, the metering section 184 can be 40
mils. Furthermore, it is contemplated that one or more turbulators
can be disposed in the trailing edge ejection holes 136. For
example, the turbulators could be disposed in the metering section
184.
[0046] It should be further appreciated that the trailing edge
ejection holes 136 as illustrated are exemplary. The trailing edge
ejection holes 136 can vary in shape or size, or both. They
ejection holes 136 themselves, or the individual parts such as the
converging section 182, the metering section 184, or the diverging
section 192 can vary in length, width, cross-sectional diameter in
order to increase the cooling efficiency of the particular airfoil
92. Additionally, the trailing edge ejection holes 136 can be
evenly spaced along the span of the trailing edge 116, or can be
unevenly spaced, or discretely positioned as a single trailing edge
ejection hole 136 or discrete groups of trailing edge ejection
holes 136 as may be beneficial to the particular airfoil 92.
Furthermore, the discrete holes 136 or groups thereof can vary in
size, shape, or orientation in order to provide increased cooling
efficiency for the airfoil 92.
[0047] Furthermore, the trailing edge ejection holes 136, when
arranged along the span-wise extent of the trailing edge 116, can
have a width that is greater for the ejection holes 136 near the
mid-span and can have a lesser width for the ejection holes 136
near the root 96 and the tip 94.
[0048] Looking at FIG. 8, a method 200 of providing a flow of
cooling fluid C through the trailing edge ejection holes 136 can
include, at 202, accelerating a flow into the trailing edge
ejection holes 136. The cooling fluid flow C is provided through
the 360 degree inlet radius 180 into the converging section 182 to
accelerate the flow. Optionally, at 204, the method 200 can include
metering the flow of cooling fluid C through the trailing edge
ejection holes 136 through the metering section 184. At 206, the
method 200 further includes decelerating the cooling fluid flow C
exiting the trailing edge ejection holes 136. Passing the cooling
fluid C through the diverging section 186 decelerates the flow
exiting the trailing edge ejection holes 136. Optionally, at 208,
the method 200 can include exhausting the cooling fluid flow C into
the trailing edge passage 138. At 210, the method 200 can
optionally, further include exhausting the cooling fluid flow C out
the trailing edge slot openings 140.
[0049] It should be appreciated that utilizing a trailing edge
ejection holes 136 can be developed by utilizing a casting core, as
opposed to other method such as drilling using electro-chemical
processes. The internal structures provide for increased airfoil
core strength during casting, improving the airfoil survival rate
during casting operations, having an increase casting yield.
Additionally, the core casting including the trailing edge ejection
holes with the 360 degree inlet radius 180, the converging section
182, metering section 184, and diverging section 186 provides for
improved airfoil cooling. Furthermore, the airfoil wake can be
reduced to improve efficiency of the airfoil 92.
[0050] It should be appreciated that application of the disclosed
design is not limited to turbine engines with fan and booster
sections, but is applicable to turbojets and turbo engines as
well.
[0051] This written description uses examples to disclose the
invention, including the best mode, and also to enable any person
skilled in the art to practice the invention, including making and
using any devices or systems and performing any incorporated
methods. The patentable scope of the invention is defined by the
claims, and may include other examples that occur to those skilled
in the art. Such other examples are intended to be within the scope
of the claims if they have structural elements that do not differ
from the literal language of the claims, or if they include
equivalent structural elements with insubstantial differences from
the literal languages of the claims.
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